Trap for drill pipe

ABSTRACT

A valve is provided for mounting in the saver sub at the lower end of a Kelly shaft. The valve is capable of remaining closed while subjected to the weight of fluid in the Kelly shaft when the saver sub is disconnected from the top length of a drill pipe to permit another pipe length to be added. The valve will open when fluid under pressure is forced into the top of the Kelly shaft.

Elite States Patent Whitmer [54] TRAP FOR DRILL PIPE [72] Inventor: JeffDavid Whitmer, Bloomfield,

Mont. 593 1 5 [22] Filed: April 8, 1971 [21] Appl.No.: 132,311

[52] US. Cl. ..137/527, 166/224, 137/515 [51] Int. Cl. ..E2lb 33/00 [58]Field of Search.....137/5l5, 515.5, 515.7, 515.3,

[56] References Cited UNITED STATES PATENTS 1,871,536 8/1932 Le Bus..137/515 3,016,914 l/1962 Keithahn ..137/527 X 51 Aug. 29, 1972 12/1962Taylor ..137/515.7X 12/1967 Fredd ..166/224 Primary Examiner-M. CaryNelson Assistant Examiner-David J. Zobkiw Attorney-Robert M. DunningABSTRACT A valve is provided for mounting in the saver sub at the lowerend of a Kelly shaft. The valve is capable of remaining closed whilesubjected to the weight of fluid in the Kelly shaft when the saver subis disconnected from the top length of a drill pipe to permit anotherpipe length to be added. The valve will open when fluid under pressureis forced into the top of the Kelly shaft.

10 Claims, 6 Drawing PATENTEUnusze m2 SHEET 2 BF 2 INVENTOR JEFF D.WH/TMEF? A ORNEY TRAP FOR DRILL PIPE This invention relates to animprovement in trap for drill pipe section and deals particularly with adevice for retaining fluid in a Kelly Shaft after it has become detachedfrom the pipe string.

BACKGROUND OF THE INVENTION In the drilling of oil wells, or information testing, it is necessary to withdraw the pipe string from thedrilled opening from time to time in order to change drill bits, installformation testing tools and the like. The pipe string is usually filledwith liquid such as oil, drill mud and the like. As the well deepens,lengths of drill pipe must be added to the pipe string between the Kellyshaft saver sub and the pipe string. As each subsequent pipe is added,the liquid contained in the Kelly shaft and the saver sub spills out onthe derrick floor, tools and crew. This spillage is wasteful andproduces extremely dangerous working conditions for the crew.

SUMMARY OF THE INVENTION The present invention resides in a novel typeof valve which is mounted inside the saver sub at the top of a pipestring in such a manner as to not interfere with the flow of fluidthrough the pipe when the valve is open. The valve is novel in that itis normally closed and is capable of remaining closed when only theweight of the fluid in the Kelly shaft rests upon the valve. However,when fluid is forced into the top of the pipe under pressure, the valvewill open to permit unrestricted flow of the fluid.

A feature of the present invention resides in the provision of a valveadapted to fit in a saver sub, the interior of which is reamed out toaccommodate the body of the valve. The valve includes a sleeve-like bodyhaving a flap valve hinged at the lower end of the body on one side ofthe fluid passage. Spring means normally urge the flap valve into closedposition so that the valve acts as a check valve to prevent the upwardflow of fluid in the pipe. The valve is normally held in closed positionby means of a yoke pivotally supported to the valve body on an axisparallel to the flap valve axis. This yoke straddles the free end of theflap valve and holds the flap valve from opening. However, when fluid isforced into the pipe under pressures normally employed in drilling, thedownward force on the flap valve will cam the yoke from beneath it, andthe flap valve will swing open.

A feature of the present invention resides in the formation of the yoke.A roller is provided on the flap valve straddling portion of the yoke orcatch designed to engage a rounded under surface of the flap valve. Theengagement of the flap valve with the roller is such that the yoke willbe pivoted out of engagement with the flap valve by the rounded valvesurface when suffrcient force is exerted against the upper surface ofthe flap valve. The force required is considerably greater than thatexerted by the weight of fluid in the Kelly shaft. Thus while addingpipe lengths, the liquid content of the Kelly shaft remains in theshaft. The Kelly shaft with its attached swivel and elbow usuallycontain about fifty gallons of fluid.

A further feature of the present invention resides in the novel means ofurging the valve into closed position. A substantially circular springis anchored to one side of the outer surface of an intermediate reduceddiameter portion of the valve body, and extends about the body. Acontrol link is connected to the valve flap on a pivot which is offsetfrom the pivot supporting the valve flap in the direction toward theaxis of the valve. This link is connected to the spring in diametricallyopposed relation to the point of anchorage. The spring is formed toresist movement of the link in a direction generally parallel to theaxis of the valve. As the flap valve opens, the pivots supporting thelink swing toward a dead center position relative to the flap valvepivot and point of connection with the valve spring.

An additional feature of my invention lies in the provision of a yokespring connecting the yoke and the control link. As the flap valveopens, and the control link moves downwardly, the yoke spring acts toexert pressure on the yoke to hold it in its extreme open position.

These and other objects and novel features of the present invention willbe more clearly and fully set forth in the following specification andclaims.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical sectional view througha pipe connection showing the valve is section.

FIG. 2 is an elevational view of the closed valve.

FIG. 3 is an elevational view of the closed valve, the view showing theside of the valve opposite that illustrated in FIG. 2.

FIG. 4 is a vertical sectional view through the closed valve.

FIG. 5 is a bottom plan view of the valve in closed position.

FIG. 6 is a bottom plan view of the valve in open position.

DESCRIPTION OF THE PREFERRED EMBODIMENT As indicated in FIG. 1 of thedrawings, the valve A is inserted in the box end or female end of asaver sub 10, the upper end of which is threaded at 11 to accommodatethe male or pin end 12 of the Kelly shaft 13. In order to accommodatethe valve A, the box end 14 is drilled out as indicated at 15 for aboutan inch below the threads 11, and then drilled as indicated at 16 at aslightly lesser diameter for a length sufficient to accommodate theentire valve A in its open position. The lower end of the bore 16 istapered as indicated at 17 to the normal pipe bore diameter 19. Thisarrangement provides a shoulder 20 between the two different diameterportions 15 and 16 for a purpose which will be set forth.

As indicated in FIG. 2 through 6 of the drawings, as well as FIG. 1, thevalve A includes at its upper end a cylindrical flange portion 21 whichis externally grooved as indicated at 22 to accommodate a sealing ring23, and as indicated at 24 to accommodate a snap ring 25.

The valve A includes an intermediate elongated tubular body 26, which isof somewhat smaller outside diameter than the cylindrical portion 21 atthe top of the valve body. An enlarged diameter portion 27 having itsouter surface on a cylindrical plane is also provided at the lower endof the valve body. The lower cylindrical portion 27 is partially cutaway in order to accommodate the working part of the valve. However, thelower cylindrical surface includes a pair of arcuate sections 29 on oneside of the valve body which extend a total angular distance of somewhatless than one half the circumference of the valve, and an arcuatesection 30 on the opposite side which also extends somewhat less thanone half the circumference of the valve body. The upper enlargeddiameter flange portion 21, the lower diameter portion 27, and theintermediate valve body 26 are all concentric, and the enlarged diameterportions fit snugly within the bored portion 61 of the box end 14. Thesnap ring 25 rests upon the shoulder 20 to support the valve body fromdownward movement. The valve body is held from upward movement by thepin end 112 of the pipe l3 should upward fluid pressure he experienced.

A flap valve 31 is designed to seal against a sealing ring 28 recessedinto the flat lower valve surface 28a forming the lower end of the valvebody at the lower end of the concentric fluid passage 3d. As is perhapsbest indicated in FIG. of the drawings, the flap valve 31 is providedwith a pair of spaced parallel pivot ears 32 projecting from the flapvalve in a generally radial direction. A pair of aligned pivot pins 33having enlarged diameter ends 33a supported in the arcuate portions 29of the enlarged flanged structure at the lower end of the valve body,and extend into the cars 32 to pivotally support the flap valve 31. Thepivot pins 33 may be held from outward movement by expansion pins 33b.As will be noted from H68. 1 and 6 of the drawings, when the flap valve31 is in its open position, the valve is completely outwardly of thedirect flow of fluid through the valve passage 34. When in closedposition, the upper surface of the flap valve is sealed against thesealing ring 23.

A valve spring anchor block 35 (see FIG. 2) is anchored to the outersurface of the intermediate portion 26 of the valve A. The anchor block35 is secured to the valve wall by a bolt 36 threaded into the wall andextending through the anchor block. The anchor block 35 is provided withtwo vertical spaced holes 37 on opposite sides of the bolt 36. Agenerally circular valve spring 39 is provided with down turned parallelends 40 which are engaged in the holes 37. The spring ring 39 is ofsomewhat greater diameter than the outer surface of the intermediateportion 26 of the valve and resists downward flexing. With reference toFIG. ll of the drawings, in the closed position of the flap valve 31,the spring is in the position indicated in dotted outline in MG. 1. Whenthe valve is open, the spring is flexed into the lower positionindicated by the broken line.

A valve control link 41 connects the valve 31 with the spring 3% and hasa lower end which is pivotally connected between the ears 32 of the flapvalve by means of a pivot pin 42. When the valve is closed, the pivotpin 42 is offset inwardly and slightly upwardly from the pivots 33connecting the flap valve 311 to the flange portion 23 of the valvebody. When the flap valve 31 is in the closed position indicated in FIG.l, the link All may exert a maximum pull upon the flap valve 31 due tothe fact that the pivot $2 is offset inwardly from the pivots 33. Thelink 41 is provided with a hook shaped upper end 43 which hooks over theportion of the spring 39 which is diametrically opposite the anchoredends of the spring ring. As the flap valve 31.

swings into open position, the axis of the pivot 42 swings about theaxis of the flap valve pivots 33 so as to move more nearly toward aposition in which the axis of the pivot 33 and &2 are more nearlyaligned with the link ll. As a result, the force tending to close thevalve decreases as the flap valve approached fully open position.

A yoke 44 forms a catch for assisting in holding the flap valve 31 inits closed position. The yoke 44 includes generally parallel sides 45which are pivotally connected to diametrically opposite sides of thevalve body by aligned pivots 46. The cross member 47 of the yoke 44 isnotched as indicated at 49 to accommodate a slightly barrel-shapedroller 50 rotatably supported upon a pivot 51 which is parallel to theaxes of the aligned pivots 46. As indicated in FIG. t, the roller 50engages the curved surface 52 on the side of the flap valve 31 mostremote from the supporting ears 32. The center of curvature of thesurface 52 is laterally offset to the left from the pivot as (as viewedin FIG. 1 of the drawings) so that the surface 52 may act as a cam topivot the yoke 3- 8 from the position shown in full lines in FIG. 1toward the position shown in dotted lines therein. As a result, thepressure against the flap valve 3i may pivot the yoke 44 into the dottedline position when this pressure reaches a predetermined amount.

The catch or yoke 44 is normally held engaged with the flap valve 31 bymeans of a spring 53 which is generally semi-circular in shape with theends of the spring engaging in substantially parallel openings 54 in thesides 45 of the yoke M. The center portion of the spring 53 is engagedin a notch 55 in the control link 43. When the flap valve 31 is inclosed position, the spring 53 will be positioned in the upper dottedline position shown in FIG. ll. When the flap valve is open, the spring53 will be positioned in the broken line lower position shown in thisfigure.

When the flap valve is closed, it is urged into the closed position bythe upward pull of the valve spring 39 which acts through the controllink 43. to exert an upward pull on the eccentrically located link pivotpin 42. However, the roller 50 on the yoke 44 engages the flap valve tohold the flap valve closed sufficiently to support fluid in the Kelleyjoint 13 above the valve. However, when fluid is forced downwardlythrough the pipe and exceeds a predetermined pressure, fluid swings theflap valve 31 downwardly about its pivots 33, this action swinging theyoke 44 about its aligned axes as until it clears the end of the flapvalve. As the flap valve opens, the control link pivot 42 swings aboutthe axis of the valve pivots 33, swinging the pivots 42 and 33, and aportion of the spring 39 engaged in the hook end 43 of the control linktoward alignment, reducing the effective upward pull exerted by thevalve spring 39.

As the control link 43! moves downwardly, the notch 55 also movesdownwardly, and in completely open position of the valve 3t, the spring53 holds the central portion of the yoke 434 out of aligiment with thepassage through the valve and holding the yoke out of the direct flow offluid passing through the valve.

when the pressure forcing fluid through the pipe is reduced and becomesstatic, the spring 39 swings the flap valve 3i. toward closed position,the pull upon the control link 41 increasing as the flap valve closes.The

end of the flap valve passes the roller 50 due to the fact that thespring 39 is much stronger than the spring 53 and the roller 5% thenrolls over the curved end 52. of the flap valve returning to itsstarting position.

As diagrammatically illustrated in FIG. 4 of the drawings, a groove 58is provided in the inner surface of the valve body having an uppersurface 56 which is normal to the axis of the valve. This groove isdesigned for engagement with the outwardly projecting shoulders 57 ofthe wedge-shaped ends 59 of a valve removing tool B. This tool, notshown in its entirety, is usually an inverted U-shaped member of springsteel with generally parallel arms 6% which support the end members 59.The tool B is used in removing the valve when desired.

It will be seen that the flap valve 31 will serve as a check valve inthe event of a reverse flow of fluid upwardly in the pipe. The valvewill remain closed unless fluid is being pumped downwardly through thepipe in which it will open completely to provide an unrestricted flowthrough the valve.

in accordance with the Patent Office Statutes, l have described theprinciples of construction and operation of my trap for drill pipes, andwhile l have endeavored to set forth the best embodiment thereof, Idesire to have it understood that changes may be made within the scopeof the following claims without departing from the spirit of myinvention.

I claim:

1. A valve adapted for use in a saver sub at the lower end of a Kellyshaft and adapted to retain fluid in the Kelly shaft when the saver subis disconnected from a drilling pipe string, the valve including:

a valve body having flanged ends adapted to fit a cylindrical bore, andan intermediate smaller diameter portion,

an axial valve passage through said valve body,

a flap valve member hingedly connected to said valve body at the outletend of said passage and pivotal from a position closing said valvepassage to a position out of alignment with said axial valve passage,

a link pivotally connected to said flap valve member on an axis parallelto, but spaced from, the hinge axis of said flap valve member,

a substantially circular spring anchored to said valve body on the sidethereof opposite to said link encircling the intermediate portion ofsaid valve body,

said link engaging said spring, and said spring resisting axial movementof said link and the opening of said flap valve member.

2. The structure of claim 1 and in which said pivotal connection betweensaid flap valve member and link is toward the valve axis from the hingeaxis.

3. The structure of claim 1 and in which the pivotal connection betweensaid link and said flap valve member swings about the hinge axis as saidflap valve member opens.

4. The structure of claim 3 and in which said hinge axis is nearalignment between said pivotal connection between said link and saidflap valve member, and said engagement between said link and said springin open position of said flap valve member.

5. The structure of claim l and including a yoke pivotally supported tothe intermediate portion of said al bd n ax's alllt dh' v s tid yo g iri c luding genirallg paral l a r r iis and a connecting portionstraddling said flap valve member,

a cam surface on said flap valve member engaging said straddling portionof said yoke, whereby when sufiicient pressure is exerted on said flapvalve member tending to open the same, said cam surface will swing saidyoke out of engagement with said flap valve member.

6. The structure of claim 5 and in which said straddling portion of saidyoke includes a roller supported on an axis parallel to said yoke axisengaging said cam surface.

7. The structure of claim 5 and including spring means urging said yoketoward flap valve member engaging position.

b. The structure of claim 7 and in which said spring means comprises anarcuate spring engaged in said link and operable, upon movement of saidlink in a direction in which said flap valve member is open to swingsaid yoke toward flap valve member disengaged position.

9. A valve including:

a valve body having an axial passage therethrough,

' a flap valve member hingedly connected to the outlet end of said valvebody and pivotal from a position closing said passage to a position outof alignment with said passage,

resilient means urging said flap valve member toward closed position,

a yoke pivotally supported by said valve body on an axis parallel to thehinge axis of said flap valve member,

said yoke including a pair of arms on opposite sides of said valve bodyand a. connecting portion straddling said flap valve member,

a rounded cam surface on said flap valve member and means on saidconnecting portion of said yoke engaging said cam means,

resilient means urging said yoke into flap valve member engagingposition,

said flap valve member operating, upon the exertion of sufficientpressure on said flap valve member tending to open the same, to forcesaid cam surface against said flap valve member engaging means and toswing said yoke out of flap valve member engaging position.

10. The structure of claim 9 and in which said flap valve memberengaging means comprises a roller having an axis parallel to the axes ofsaid yoke and said flap valve member.

* a a a

1. A valve adapted for use in a saver sub at the lower end of a Kellyshaft and adapted to retain fluid in the Kelly shaft when the saver subis disconnected from a drilling pipe string, the valve including: avalve body having flanged ends adapted to fit a cylindrical bore, and anintermediate smaller diameter portion, an axial valve passage throughsaid valve body, a flaP valve member hingedly connected to said valvebody at the outlet end of said passage and pivotal from a positionclosing said valve passage to a position out of alignment with saidaxial valve passage, a link pivotally connected to said flap valvemember on an axis parallel to, but spaced from, the hinge axis of saidflap valve member, a substantially circular spring anchored to saidvalve body on the side thereof opposite to said link encircling theintermediate portion of said valve body, said link engaging said spring,and said spring resisting axial movement of said link and the opening ofsaid flap valve member.
 2. The structure of claim 1 and in which saidpivotal connection between said flap valve member and link is toward thevalve axis from the hinge axis.
 3. The structure of claim 1 and in whichthe pivotal connection between said link and said flap valve memberswings about the hinge axis as said flap valve member opens.
 4. Thestructure of claim 3 and in which said hinge axis is near alignmentbetween said pivotal connection between said link and said flap valvemember, and said engagement between said link and said spring in openposition of said flap valve member.
 5. The structure of claim 1 andincluding a yoke pivotally supported to the intermediate portion of saidvalve body on an axis parallel to said hinge axis, said yoke includinggenerally parallel arms and a connecting portion straddling said flapvalve member, a cam surface on said flap valve member engaging saidstraddling portion of said yoke, whereby when sufficient pressure isexerted on said flap valve member tending to open the same, said camsurface will swing said yoke out of engagement with said flap valvemember.
 6. The structure of claim 5 and in which said straddling portionof said yoke includes a roller supported on an axis parallel to saidyoke axis engaging said cam surface.
 7. The structure of claim 5 andincluding spring means urging said yoke toward flap valve memberengaging position.
 8. The structure of claim 7 and in which said springmeans comprises an arcuate spring engaged in said link and operable,upon movement of said link in a direction in which said flap valvemember is open to swing said yoke toward flap valve member disengagedposition.
 9. A valve including: a valve body having an axial passagetherethrough, a flap valve member hingedly connected to the outlet endof said valve body and pivotal from a position closing said passage to aposition out of alignment with said passage, resilient means urging saidflap valve member toward closed position, a yoke pivotally supported bysaid valve body on an axis parallel to the hinge axis of said flap valvemember, said yoke including a pair of arms on opposite sides of saidvalve body and a connecting portion straddling said flap valve member, arounded cam surface on said flap valve member and means on saidconnecting portion of said yoke engaging said cam means, resilient meansurging said yoke into flap valve member engaging position, said flapvalve member operating, upon the exertion of sufficient pressure on saidflap valve member tending to open the same, to force said cam surfaceagainst said flap valve member engaging means and to swing said yoke outof flap valve member engaging position.
 10. The structure of claim 9 andin which said flap valve member engaging means comprises a roller havingan axis parallel to the axes of said yoke and said flap valve member.